Activiti rest自己封装了一个接口为什么就报错了呢?报错

*/
  	public List<TaskFormResoponse> taskFormResoponses(FormService formService,TaskService taskService,String assignee) {
  		TaskFormResoponse taskForm=null;
  		List<TaskFormResoponse> listTaskForm=new ArrayList<TaskFormResoponse>();
  		
  		
  		List<Task> listTask=taskService.createTaskQuery().taskAssignee(assignee).list();
  		logger.info("listTasktostring: "+listTask.toString());
  		logger.info("listTask: "+listTask.size());
  		
  		//taskService.createTaskQuery().orderByTaskId().list();
  		for(Task task:listTask){
 			 taskForm=new TaskFormResoponse();
 			 
 			 taskForm.setFormDate(formService.getTaskFormData(task.getId()));
  			 taskForm.setTask(task);
  			logger.info("task: "+task.toString());
  	  		logger.info("form: "+formService.getTaskFormData(task.getId()));
  			 listTaskForm.add(taskForm);
  		}
  		
  		return listTaskForm;
		
	}

{"message":"Bad request","exception":"Could not write content: lazy
 loading outside command context (through reference chain: java.util.ArrayList[0]-
>org.activiti.rest.service.api.rewrite_yadong.TaskFormResoponse[\"task\"]->org.activiti
.engine.impl.persistence.entity.TaskEntity[\"variableInstances\"]); nested except
ion is com.fasterxml.jackson.databind.JsonMappingException: lazy loading outside command
 context (through reference chain: java.util.ArrayList[0]->org.activiti.rest.service.api
.rewrite_yadong.TaskFormResoponse[\"task\"]->org.activiti.engine.impl.persistence.entity.
TaskEntity[\"variableInstances\"])"}